Investigation of the enhanced emission of QDs due to the surface plasmon of periodic structures

由於金屬表面的週期性結構照光後產生的表面電漿具有特殊的電場分布與 光學性質，並且該結構可以縮小到奈米尺度，因此在奈米光子學理有良好的前瞻 性與應用價值。此篇論文將討論金屬介電質奈米複合光柵結構對於量子點的發光 增益影響，在變入射角的光柵內部電場強度模擬中可以發現此結構具有法布里- 珀羅共振性質，透過調整光柵週期、共振腔長度，以及不同的金屬材料，我們可 以操控共振波長與表面電漿的性質，來達到更好的增益效果。The periodic structure on metal surface has the nature that under illumination, it will cause surface plasmon propagate among the structure. Surface plasmon bears a unique electric field distribution and photonic properties, when the structure is reduced to nanoscale. In this thesis, we will investigate the enhancement due to a hybrid nanostructure consisting of dielectric-embedded metallic grating. It is found that this novel structure possesses Fabry-Pe rot resonance property through a simulation of electric field strength with varying incident angle. By adjusting the grating period, resonance cavity length and different metals, it is possible to control the resonance wavelength and the properties of surface plasmon to obtain a better enhancement of the light emission arising from semiconductor quantum dots.口試委員審定書 i 致謝 ii 中文摘要 iii Abstract iv Contents v List of Figures vii 1 Introduction 1 References…………………………………………………………………………4 2 Theoretical Background 6 2.1. Definition of plasmon……………………….………….……………...6 2.2. Surface plasmon polarition at interface between dielectric and metal……..9 2.3. Excitation of surface plasmon polaritons at planar interfaces……….……11 2.4 Introduction of quantum dots (QDs)………………………………………16 2.5 Photoluminescence………………………………………………………17 References……………………………………………………………………….20 3 Experimental Apparatuses 22 vi 3.1 Electron beam lithography (EBL)………………………………….………22 3.2 Scanning electron microscopy (SEM)………………….…………………..26 3.3 Photoluminescence (PL) spectroscopy……………………………………..29 References………………………………………………………….…………...33 4 Optical properties of QDs in periodic structure 34 4.1 Introduction………………………………………………….……………..34 4.2 Sample preparation……………..…………………….…………………….35 4.3 Design of experiments………….…………………………………………..37 4.4 Results and discussions………….……………………………………….38 References………………………………………………………………………..46 5 Conclusions 4